A series of lanthanide germanate cluster organic frameworks

Abstract

Six new lanthanide (Ln) germanate cluster organic frameworks (LnGeCOFs) derived from {Ln8Ge12} cage cluster units {[Nd(pza)2(H2O)] [Nd8Ge12(μ3-O)24E12(pza)(H2O)12]}·3H2O (1), {[Dy(CH3COO)(CO3)(H2O)]2[Dy8Ge12(μ3-O)24E12(H2O)12]}·11H2O (2), {[TbGeE(HO)2O(pza) (H2O)]2[Tb8Ge12(μ3-O)24E12(H2O)6]}·18H2O (3), {[DyGeE(HO)2O(C3H5NO2)(H2O)]2[Dy8Ge12(μ3-O)24E12(H2O)8]}·8H2O (4), {[Tb(pca)2 (H2O)]3[Tb8Ge12(μ3-O)24E12(H2O)4]}·(OH)3·10H2O (5) and {[Dy(pza)2(H2O)][Dy(pza)2(H2O)2][Dy(pza)3(H2O)][Dy8Ge12(μ3-O)24E12(pza)(HCOO) (H2O)6]}·5H2O (6) have been hydrothermally synthesized and structurally characterized. Increasing the amount of the second ligands can induce not only the assembly from 1 to 5, 6 based on Ln oxides as the starting sources, but also the assembly from 2 to 3, 4 based on Ln salts as the starting sources. The successful preparation of these LnGeCOFs suggests the importance of the second ligands in the structural construction of 1-6. To our knowledge, 1 is the first example that includes right- and left-handed helical chains among LnGeCOFs based on bis(carboxyethylgermanium)sesquioxide. 2, 4 and 6 are the first dysprosium incorporated organogermanates based on bis(carboxyethylgermanium)sesquioxide. 4 and 5 display very open framework structures with a solvent-accessible volume of 34.6% for 4 and 35.0% for 5. Moreover, the solid-state photoluminescence properties of 1, 3 and 5 have been investigated at room temperature and they exhibit the characteristic emission bands derived from Ln cations.

Cu42Ge24Na4—A Giant Trimetallic Sesquioxane Cage: Synthesis, Structure, and Catalytic Activity

“…Nevertheless, no examples of such an encapsulation have been reported so far for metallasesquioxanes. Furthermore, this feature of product 1 as well as the additional coordination of chlorine atoms to the copper ions point to a possible template effect exerted by CHCl 3 during the assembly of cage metallagermsesquioxanes, which was not emphasized in previous reports [20][21][22][23][24][25][26][27][28][29][30].…”

“…Indeed, the whole complex of 1 is built up of two similar cage units of unprecedented Cu 21 Ge 12 -nuclearity. An isolation of such metal-rich (the M/Ge ratio exceeds 1/1) product has never been reported for any metallagermaniumsesquioxanes [20][21][22][23][24][25][26][27][28][29][30]. In terms of topology, the spherical shape of cage-like components of product 1 could be compared only to non-dimeric Cu(I)-based silsesquioxane reported by the team of Prof. Zhu and Prof. Roesky [31].…”

“…It is ultimately surprising but to the best of our knowledge germanium sesquioxane ligands that are the closest analogues of silsesquioxanes, have been scarcely studied in the context of a possible molecular design of metallacomplexes so far. We could mention here only the use of (i) bis(carboxyethyl)germanium sesquioxide [20][21][22][23][24][25][26][27] in hydrothermal reactions and (ii) PhGe(OMe) 3 [28,29] in the self-assembly synthesis.…”

Hexacoppergermsesquioxanes as complexes with N-ligands: Synthesis, structure and catalytic properties

“…Hydrothermal method was reported for isolation of MOF-like objects starting from germanium sesquioxide [50e59]. Some of these products were isolated in the presence of additional ligands, namely 2-picolinic acid [50,56,57], 2-pyrazinecarboxylic acid [56,57], 2,6-pyridinedicarboxylic acid [57] or 1,10-phenanthroline [58,59]. These unusual products demonstrated luminescent [50,51,56,57,59] sorption (of Ar gas [50]) properties and high thermal stability [50e59].…”

A Series of Lanthanide–Germanate Oxo Clusters Decorated by 1,10-Phenanthroline Chromophores

“…As a result, the d-block metal chromophores incorporating Ln ions (Ln 3+ ) can give various luminescent d–f heterometallic oxo clusters, where the intensities of characteristic lanthanide emissions are significantly enhanced. Compared with numerous d–f heterometallic oxo clusters, the p–f heterometallic oxo clusters containing lighter p-block metal and Ln 3+ are less explored, mainly because hard Lewis acidic p-block metal ions coexist with difficulty with Ln 3+ in the same framework of heterometallic oxide clusters in solution, which could result from the obvious difference in the radii and oxophilic of lighter p-block metal and Ln 3+ . The lighter p-block Ge ion is often used for constructing good phosphor hosts of germinates with high density and luminescent conversion efficiency because of the high defect concentration of the germanate matrix .…”